1. Field of the Invention
This invention relates to a solderless termination system. In particular, it relates to the type of such systems where a wire is engaged and held by blades or jaws. In further particular, it relates to the type of such systems adapted for insulation piercing as well as engaging and holding a wire.
2. Description of the Prior Art
Electrical termination systems are known in myriad forms and sizes. The type of system of interest in the present description provides, as a means for retaining a wire, a pair of facing blades or jaws which may be, before insertion of a wire, in a contact or appropriately spaced apart. Conventionally, blades are adapted to grip a wire between them for mechanical and electrical contact. Often, a lead-in portion is provided where the contact portion of the blades opens to provide convenient positioning and gradual gripping of the wire. Such structures as are shown in the prior art may also enable the insulation surrounding the wire to be pierced as it is inserted between the blades. Common applications of such termination systems are in splicing wires and in the wire terminating end of connectors.
There are a number of factors and problems important in an acceptable insulation piercing solderless termination system. Some of these factors and problems are more pronounced with regard to so called miniature termination systems or high density systems where elements are quite close together.
One of the most important (if not the most important) performance factors relates to contact resistance. More accurately, this factor relates to the change in contact resistance between the terminated wire and the terminating system after being subject to time and hostile environments.
The physical strength and durability of the connection between the wire and the termination system is also important.
Other factors relate to manufacturability and within that general subject, to the level of confidence found for terminations passing the various acceptance tests. It should be understood that with high volume production, the number of faulty pieces should be small and predictable with high level of confidence.
The termination system described below has been found to perform very well under a variety of physical and electrical performance conditions and to meet the needs for manufacturability. In terms of change in contact resistance, under hostile environments and use tests, excellent results have been obtained.
It is further notable that termination systems of the type herein described have both civilian and military uses and are particularly used in telephone systems. Production and utilization volumes are high and reliability requirements within the performance parameters specified by users are very stringent. In one exemplary application, the criterion set is that, under the defined test conditions, no more than 1 out of 10,000 terminations may exceed a change in contact resistance of 0.25 milliohms at the 95% confidence level.